An operator of a network-based marketplace may be interested in the behavior of buyers and sellers that conduct commerce within a network-based marketplace. For example, the operator may be interested in identifying a seller that consistently sells a high volume of goods. One reason might be to encourage such behavior by providing a reward. Another reason might be to categorize the seller as one that should receive VIP service. As another example, the operator may be interested in identifying fraudulent activity in the network-based marketplace. The operator has good reason to remove the offending party because identification and removal of the user may increase the overall trust and safety for all buyers and sellers in the network-based marketplace.
Operators face technical challenges in identifying outlying behavior in a network-based marketplace. One approach for identifying outlying behavior has been to establish a rules base system. The behavior of buyers and sellers are compared against the rules to detect outlying behavior. Operators will usually have some immediate success with such systems but have found, by experience, that the effectiveness of a rules base system will typically diminish with time. For example, a rules based system to identify fraudulent activity will decrease in effectiveness as the perpetrators of the fraudulent activity become aware of the rules and adjust their behavior to avoid detection.